(a) Field of the Invention
The present invention relates to an apparatus and a method for spatial filtering by estimating an angle of deviation for line of sight of a user.
(b) Description of the Related Art
As the number of users of portable terminals has rapidly increased, direct communication system between the terminals, such as Bluetooth or WiFi P2P, has been extended. In the direct communication system between the terminals, surrounding terminal scanning, list displaying, user selecting, and setting processes are performed until a communication link is set with the selected target device.
In these processes, a long time is required and a communication amount is increased. The user should recognize priori information on corresponding terminals, which is inconvenient. Therefore, in order to increase efficiency of direct communication between the terminals, a method capable of rapidly performing a connection and providing convenience to the user by decreasing a search range to only a target terminal is required.
In the direct communication system between a plurality of terminals present at a distance in close proximity to the user and the terminal, a beamforming technology limits the number of connectable terminals to the number of terminals present in a range of a beam to facilitate selection of a target and connection with the target. In addition, overhead used for communication may be decreased through beamforming. In the beamforming technology, the narrower the beam width, the higher capability it has of distinguishing only terminals present in a specific direction. Generally, the beam width is determined depending on the number of antennas.
The larger the number of antennas, the narrower the beam width, but the wider the space occupied by the antennas at a given frequency. Therefore, spatial resolving power is determined depending on sizes and the number of antennas that may be mounted in the portable terminals. When the number of antennas is increased at a given frequency, it is difficult to mount the increased number of antennas in the portable terminals.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.